This invention relates to a fuel dispensing nozzle, such as may be utilized to dispense a variety of liquid fuels (e.g., gasoline, diesel fuel and the like), and particularly to such a fuel dispensing nozzle which automatically shuts off the flow of fluid upon the fuel tank of the vehicle becoming filled.
Such automatically operable fuel dispensing nozzles are in wide commercial use and have long been known in the art. Reference may be made to such co-assigned U.S. Pat. Nos. 4,016,910 and 4,031,930 for more complete disclosures of automatically operable shut-off fuel dispensing nozzles. Generally, these automatic fuel dispensing nozzles have a main poppet valve which is operable upon actuating a dispenser handle which in turn is pivotally attached to the nozzle. Upon actuating the handle, a stem extending exteriorally of the dispensing nozzle housing is displaced axially into the housing so as to move a poppet valve member from its closed position in which it sealingly engages a valve seat thereby to permit the flow of fuel through the dispensing nozzle and into the fuel tank of an automobile or the like. As is conventional, these automatic shut-off fuel dispensing nozzles include a diaphragm actuator or the like which is responsive to the fuel level in the tank reaching the end of the dispensing spout of the nozzle and covering up a vent hole thereby preventing communication between one side of the diaphragm actuator and the atmosphere in which case a vacuum generated by the flow of fuel through the dispensing nozzle causes the front pivot or fulcrum for the dispensing handle to be released which in turn moves the handle out of engagement with the poppet valve stem, thus allowing the poppet valve to close terminating the flow of fuel from the nozzle.
Various poppet valve configurations are currently used in existing fuel dispensing nozzles. Typically, these poppet valves are complex members requiring considerable machining and are thus difficult to assemble and expensive to manufacture. Also, in some instances, prior art poppet valves have been known to permit vacuum to develop within various component parts of the valve or to permit air to enter the poppet valve, thus having a cushioning effect on the operation of the valve so that the dispensing nozzle will not instantaneously terminate the flow of fluid or may cause a jumping action in the valve's operation, resulting in erractic flow of fuel which may have a deleterious effect on metering of the flow of fuel.
Reference may be made to such U.S. Pat. Nos. 3,273,609, 3,653,415, 4,199,012, 4,139,032, 4,139,032, 4,196,759, 4,203,478, 3,196,908, 3,085,600, and 3,877,480, for disclosures of automatic shut-off dispensing nozzles having a variety of poppet valve configurations generally in the broad field of this invention.
Further, reference may also be made to the patentee's co-assigned U.S. Pat. No. 4,397,447, issued Aug. 9, 1983, which discloses an improved poppet valve construction for an automatic shut-off fuel dispensing nozzle.
While these prior art patents disclose a variety of poppet and other type valves for controlling the flow of fuel through the dispensing nozzle, and while many of these valves worked well for their intended purposes, many of these prior valves did have certain shortcomings. More particularly, since it was desirable to have relatively fast flow rates of fuel through the dispensing nozzle, relatively large diameter poppet valves were required so as to ensure a substantially unimpeded flow of fuel through the dispensing nozzle when the dispensing nozzle handle was actuated. However, to ensure that the flow of fuel was positively blocked when the valve was closed, such a large area poppet valves required a relatively strong spring to ensure that the valve remained in its closed position without leakage. These strong valve biasing springs required considerable effort to overcome upon actuating the dispensing nozzle handle which may be uncomfortable for the user.
Further, many of the prior art poppet valves were relatively complex in construction and were difficult to fabricate, to install, and to service in the field.